This invention relates to 1,3-bis(2,2,2-fluorodinitroethoxy)-2,2-bis(difluoramino)propane and to a process for its preparation. More particularly, this invention concerns itself with a process for effecting the difluoramination of 1,3-bis(2,2,2-fluorodinitroethoxy)-2-propanone and to the product produced thereby.
Compounds containing both fluorodinitro and gemminal bis(difluoramino) functional groups are finding application in formulations of advanced energetic propellants. They have been found to be especially useful as high energy plasticizers for propellant and explosive formulations.
The basic reactions for producing these high energy functional groups are the direct fluorination of dinitrocompounds or a reaction between a ketone and difluoramine.
Because the ether function usually leads to good low temperature properties and chemical stability of energetic molecules, it was desirable to synthesize an ether containing the maximum number of these energetic groups. However, the reaction of ketones with difluoramine to give the corresponding gemminal bis(difluoramino) derivative is extremely difficult since it is sensitive to the electronic properties of substituents. Substituents with ether functions are difficult to react in this way because the ether oxygen is protonated by strong acid and the resulting positive charge inhibits protonation of the carbonyl group, which is necessary for difluoramination.
In attempting to synthesize 1,3-bis(2,2,2-fluorodinitroethoxy)-2,2-bis(difluoramino)propane, a material particularly useful as a plasticizer for propellant compositions, it has been found that the problems encountered heretofore can be abrogated by the process of this invention which accomplishes difluoramination by effecting a reaction between difluoramine and 1,3-bis(fluorodinitroethoxy)-2-propanone in a strong acid medium. The propanone starting material for the reaction referred to above is initially prepared by the addition of fluorodinitroethanol to epichlorohydrin followed by oxidation. The resulting ketone is then reacted with difluoramine and oleum to give a high yield of 1,3-bis(2,2,2-fluorodinitroethoxy)-2,2-bis(difluoramino)propane, hereinafter referred to as SYEP.